Certain known laying vessels for laying pipelines on the bed of a body of water are described in PCT Patent Application No. WO 2009/082191 A1, PCT Patent Application No. WO 2009/145607 A1, and PCT Patent Application No. WO 01/07812 A1. As is known, abandon and recover systems (“A&R systems”) are used when laying work is interrupted by bad weather, and the pipeline being laid has to be abandoned on the bed of the body of water and recovered later, to continue laying work, when the weather improves. Laying vessels also have to be configured to cope with emergency situations—especially sudden changes in weather—so as to switch rapidly from laying mode to pipeline abandon mode.
To switch as fast as possible from laying to abandon mode, the A&R system is normally fitted directly to the laying tower, as shown in PCT Patent Application No. WO 2009/145607 A1 and PCT Patent Application No. WO 01/07812 A1, or inside the laying tower, as shown in PCT Patent Application No. WO 2009/082191 A1.
Known technical solutions often have the drawback of impeding access to the laying tower, and not always enabling easy positioning of the haul line on the sheave assembly. In this connection, it should be appreciated that the haul line is defined by at least one rope of considerable size and weight per unit length, and which can only be maneuvered using special cranes.